Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 2800c Report Date: 09-May-96:17:22 Version: ********** Check-in Date: ********** 1.Proposal Title: MAGNETIC FIELDS OF PECULIAR TYPE A VARIABLE STARS ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID STELLAR ASTROPHYSICS GO/AM 1 Long Term yrs 2800 Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Mr. Peter J. Kandefer HST- AMATEUR ASTRONOMER USA 203 496-7373 ELECTRICAL ENGINEER ------------------------------------------------------------------------------------ 7. Abstract High resolution spectrograph (HRS) is used to observe one peculiar type A star to study spectral lines indicating the presence of a strong magnetic field. Light variations during the target star's 5.0887-day period are already correlated to magnetic field variations. A sequence of observations on a single star is required to obtain the desired data. ------------------------------------------------------------------------------------ 8. Scientific Key Words: VARIABLE, CHEMICALLY PECULIAR STAR, LINE, ABSORPTION UV, MAGNETIC FIELD ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 1.80 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 2800c PI: Mr. Peter J. Kandefer Proposal Title: MAGNETIC FIELDS OF PECULIAR TYPE A VARIABLE STARS ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Mr. Peter J. Kandefer HST - AMATEUR ASTRONOMER USA ------------------------------------------------------------------------------------ 2. Scientific Justification. Certain variable stars that do not pulsate show unusually intense spectral lines of the ions of strontium, silicon and chromium, or of the rare earths. These lines may vary in strength in periods which range from 0.5 to 314 days, with one having a period of 23 years or so. Often, one set of lines will actually weaken (such as those of the rare-earths), while another set strengthens (such as those of chromium) and a certain "null" line will show no variation. The analysis reveals the broadening, splitting and different polarization of the lines due to the Zeeman effect, in which a spectral line is split into several components which have a characteristic polarization. The stellar magnetic fields are variable, with some exhibiting polarity reversals, and the magnetic variability is linked to the phase of the spectrum changes. Most stellar magnetic fields range from about 500 gauss to 3,000 gauss, while the maximum detected is 34,000 gauss. These lines are referred to as "peculiar" and the suffix "p" is added to the star's spectral designation. The best studied peculiar stars belong to spectral type A and are grouped in the Alpha Canum Venaticorum class of variable stars, named after the prototype star. The spectral changes are generally interpreted to show areas of elemental overabundances which concentrate at the star's magnetic poles, per the oblique rotator model. ------------------------------------------------------------------------------------ 3. Description of proposed observations. The spectral lines of Ap stars show particularlly prominent lines of Sr, Cr and Eu in spectral types A0 through A2, while other lines are seen in stars of adjacent types. The target star selected shows changes in the lines of chromium, europium and calcium, from earth based measurements. Measurements of the amount of polarization in the "wings" of the spectra by the HRS will allow a determination of the strength of the magnetic field. Additional mathematical analysis will provide a determination of the physical geometry of the star's magnetic field orientation. Note that there are eleven repetitions of the HRS. HRS lines are: 2959.9, 2340.9(EuIIa), 2350.3, 2344.0(SiII), 2061.6, 2065.5(CrII), 2965.1(FeI), 2585.9(FeII), 2364.9 and 2366.8, 3013.03 and 3015.19 (CrI), 2964.63 and 3105.55 (Fe II), and 2965.26 and 3121.78 A (FeI). ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. These peculiar Ap stars are located just above the main sequence of the H-R diagram, in about the same relationship to the normal type A stars as the Beta Canis Majoris stars do to the normal type B stars. The group's location on the color magnitude diagram indicates that these stars produce an excess of UV light. Earth based observations have been made primarily from 3,400A to 11,000A, and the proposed observing program extends the spectral observations to the UV with use of the HRS With an expected light variation of 0.03 magnitude and UV spectral measurements to be made, a series of orbiting observations is necessary. Photographic detection of magnetic fields from the earth has a lower limit of about +/- 100 gauss. The target star is expected to have a magnetic field of about the same magnitude, again illustrating the need for the HST. Page 3 ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. As part of the HST Amateur Astronomer project, the following recommended allocations have been tentatively approved for this program: -Unocculted spacecraft time (cycle 1)........8.5 hours -Parallel time (cycle 1).....................0.0 hours -Duration of observing program...............1 year -Unocculted spacecraft time (future years)...0.0 hours A repetitive series of measurements of this variable star is required to obtain the proposed objectives. These measurements can be spread out over a 5 day period in order to "capture" the 5.0887 day variation of the target star HD112185 (HR 4905, Epsilon Ursae Majoris) which changes its brightness from 1.76 to 1.79 magnitude (V). The star's position was verified with GSS at STScI, and is given in the target log. Observation of a single star is made. This is informational only: PERIOD 5.0887D +/- 0.001D; ZERO-PHASE JD2447804.46117 +/- 0.001D; The PI requests that all phases of the period be covered by following the AFTER special requirements. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. The type Ap magnetic variables have measured periods which are relatively constant for periods of decades. Thus the time of the measurements can be specified well in advance. This is detailed in the exposure log. The magnetic positive pole has been determined at phase 0.95 +/- 0.02, per 1990 ground-based measurements. During the first six months following the orbiting of the HST, the calibrations and prove-out of the instruments are expected to provide better than 1.0 percent accuracy in the HRS. This accuracy is sufficient for the proposed program. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The HRS data will also follow the automatic "pipeline" data processing of the Routine Science Data Processing (RSDP). The wide range of General Analysis facilities of the Science Data Analysis System (SDAS) are very suitable to the analysis to be performed on the finalized data. This involves evaluating selected lines, a search for the centroid, and other timed data curve fitting techniques already avilable. For this program, a superposition of selected HRS data is very desirable, in order to determine additional magnetic field characteristics. Data analysis will be at STScI. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. There are some plans for coordinating photometric observations with the AAVSO, which are the entire responsibility of the PI. Because of the brightness of the object, no special positioning is needed. Acquisition of the HRS with the 2.0 aperture will be adequate. The data will normally be restricted for one year after completion of the program. The discretionary time at STScI should allow for targets of opportunity to be handled with all necessary expediency. This is not required here. Note that GTO 1182 has an observing sequence of 23 stars of types B and A. While the GTO program centers on 16 type B9pHgMn stars, the observations detailed here are for a single type A0p star. Selection of this target avoided any overlap and separation is maintained. ------------------------------------------------------------------------------------ 9. Description of previous HST work. Not Applicable. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). The P.I. has limited data analysis capabilities with primary access to a PC-XT computer with word processing (WordPerfect) and math analysis (Mathcad). Library facilities can be utilized at Yale in New Haven, Connecticut, and at the Harvard/Smithsonian Center for Astrophysics in Cambridge, Massachusetts. The assistance of the STScI in providing for transportation and overnight accomodations is gratefully acknowleged. Page 4 ------------------------------------------------------------------------------------ 11. Address Information Name: PETER J. KANDEFER Category: PI Institution: HST- AMATEUR ASTRONOMER Address: 41 SOUTH ROAD City: NEW HARTFORD State: CT Zip Code: 06057 Country: USA Telephone: (203) 496-7373 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 2800c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD112185 STAR;VARIABLE;CHEMICALL RA=12H 54M 1.517S +/-1S, J2000 1 V=1.77 Y PECULIAR STAR;, DEC=55D 57' 35.65"+/-1" 2 B-V=-0.02 MAGNETIC 3 U-B=+0.02 FIELD;UV;LINE;ABSORPTIO Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1900.00 0.0091 +/- 0.0001 -0.0110 +/- 0.0010 0.0093 +/- 0.0160 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 2800c [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1.5 DEFINE HD112185 HRS IMAGE 2.0 MIRROR-A2 1 96.8S 1 1 CYCLE 1 / 1.5-11 SPEC Comments: TAKE MAP AFTER CENTERING ------------------------------------------------------------------------------------------------------------------------------------ 2 ^ ^ ^ ACCUM 0.25 ECH-B 2959.9 FP-SPLIT=STD 1 57.6S 100 1 1 GROUP 2-11 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 3 ^ ^ ^ ^ ^ ^ 2340.9 FP-SPLIT=STD 1 57.6S 100 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 4 ^ ^ ^ ^ ^ ^ 2350.3 FP-SPLIT=STD 1 57.6S 100 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 5 ^ ^ ^ ^ ^ ^ 2061.6 FP-SPLIT=STD 1 57.6S 100 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 6 ^ ^ ^ ^ ^ ^ 3015 FP-SPLIT=STD 1 57.6S 100 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 7 ^ ^ ^ ^ ^ ^ 2965.1 FP-SPLIT=STD 1 57.6S 100 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 8 DEFINE HD112185 HRS ACCUM 0.25 ECH-B 2585.9 FP-SPLIT=STD 1 57.6S 100 1 1 SPEC ------------------------------------------------------------------------------------------------------------------------------------ 9 DEFINE HD112185 HRS ACCUM 0.25 ECH-B 2364.9 FP-SPLIT=STD 1 57.6S 100 1 1 SPEC ------------------------------------------------------------------------------------------------------------------------------------ 10 DEFINE HD112185 HRS ACCUM 0.25 ECH-B 3121.78 FP-SPLIT=STD 1 57.6S 100 1 1 SPEC ------------------------------------------------------------------------------------------------------------------------------------ 11 ^ ^ ^ ^ ^ ^ 3105.55 FP-SPLIT=STD 1 57.6S 100 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 15 HD112185 HRS ACQ 2.0 MIRROR-A2 FAINT=6560.5 1 5S 1 1 ONBOARD ACQ FOR SEARCH-SIZE=5 15.01 LOCATE=YES CYCLE 1 Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 15.01 HD112185 HRS ACQ/ 2.0 MIRROR-A2 1 9.2S 1 1 ONBOARD ACQ FOR PEAKUP 15.1 CYCLE 1 Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 15.1 USE SPEC ------------------------------------------------------------------------------------------------------------------------------------ 16 HD112185 HRS ACQ 2.0 MIRROR-A2 FAINT=6560.5 1 5S 1 1 ONBOARD ACQ FOR SEARCH-SIZE=5 16.01 LOCATE=YES CYCLE 1 AFTER 15 BY 12H +/- 2 H Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 16.01 HD112185 HRS ACQ/ 2.0 MIRROR-A2 1 9.2S 1 1 ONBOARD ACQ FOR PEAKUP 16.1 CYCLE 1 Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 2800c [ 7] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 16.1 USE SPEC ------------------------------------------------------------------------------------------------------------------------------------ 17 HD112185 HRS ACQ 2.0 MIRROR-A2 FAINT=6560.5 1 5S 1 1 ONBOARD ACQ FOR SEARCH-SIZE=5 17.01 LOCATE=YES CYCLE 1 AFTER 15 BY 24H +/- 2 H Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 17.01 HD112185 HRS ACQ/ 2.0 MIRROR-A2 1 9.2S 1 1 ONBOARD ACQ FOR PEAKUP 17.1 CYCLE 1 Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 17.1 USE SPEC ------------------------------------------------------------------------------------------------------------------------------------ 18 HD112185 HRS ACQ 2.0 MIRROR-A2 FAINT=6560.5 1 5S 1 1 ONBOARD ACQ FOR SEARCH-SIZE=5 18.01 LOCATE=YES CYCLE 1 AFTER 15 BY 36H +/- 2 H Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 18.01 HD112185 HRS ACQ/ 2.0 MIRROR-A2 1 9.2S 1 1 ONBOARD ACQ FOR PEAKUP 18.1 CYCLE 1 Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 18.1 USE SPEC ------------------------------------------------------------------------------------------------------------------------------------ 19 HD112185 HRS ACQ 2.0 MIRROR-A2 FAINT=6560.5 1 5S 1 1 ONBOARD ACQ FOR SEARCH-SIZE=5 19.01 LOCATE=YES CYCLE 1 AFTER 15 BY 48H +/- 2 H Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 19.01 HD112185 HRS ACQ/ 2.0 MIRROR-A2 1 9.2S 1 1 ONBOARD ACQ FOR PEAKUP 19.1 CYCLE 1 Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 19.1 USE SPEC ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 2800c [ 8] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 20 HD112185 HRS ACQ 2.0 MIRROR-A2 FAINT=6560.5 1 5S 1 1 ONBOARD ACQ FOR SEARCH-SIZE=5 20.01 LOCATE=YES CYCLE 1 AFTER 15 BY 60H +/ - 2 H Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 20.01 HD112185 HRS ACQ/ 2.0 MIRROR-A2 1 9.2S 1 1 ONBOARD ACQ FOR PEAKUP 20.1 CYCLE 1 Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 20.1 USE SPEC ------------------------------------------------------------------------------------------------------------------------------------ 21 HD112185 HRS ACQ 2.0 MIRROR-A2 FAINT=6560.5 1 5S 1 1 ONBOARD ACQ FOR SEARCH-SIZE=5 21.01 LOCATE=YES CYCLE 1 AFTER 15 BY 72H +/- 2 H Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 21.01 HD112185 HRS ACQ/ 2.0 MIRROR-A2 1 9.2S 1 1 ONBOARD ACQ FOR PEAKUP 21.1 CYCLE 1 Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 21.1 USE SPEC ------------------------------------------------------------------------------------------------------------------------------------ 22 HD112185 HRS ACQ 2.0 MIRROR-A2 FAINT=6560.5 1 5S 1 1 ONBOARD ACQ FOR SEARCH-SIZE=5 22.01 LOCATE=YES CYCLE 1 AFTER 15 BY 84H +/- 2 H Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 22.01 HD112185 HRS ACQ/ 2.0 MIRROR-A2 1 9.2S 1 1 ONBOARD ACQ FOR PEAKUP 22.1 CYCLE 1 Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 22.1 USE SPEC ------------------------------------------------------------------------------------------------------------------------------------ 23 HD112185 HRS ACQ 2.0 MIRROR-A2 FAINT=6560.5 1 5S 1 1 ONBOARD ACQ FOR SEARCH-SIZE=5 23.01 LOCATE=YES CYCLE 1 AFTER 15 BY 96H +/- 2 H Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 2800c [ 9] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 23.01 HD112185 HRS ACQ/ 2.0 MIRROR-A2 1 9.2S 1 1 ONBOARD ACQ FOR PEAKUP 23.1 CYCLE 1 Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 23.1 USE SPEC ------------------------------------------------------------------------------------------------------------------------------------ 24 HD112185 HRS ACQ 2.0 MIRROR-A2 FAINT=6560.5 1 5S 1 1 ONBOARD ACQ FOR SEARCH-SIZE=5 24.01 LOCATE=YES CYCLE 1 AFTER 15 BY 108H +/- 2 H Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 24.01 HD112185 HRS ACQ/ 2.0 MIRROR-A2 1 9.2S 1 1 ONBOARD ACQ FOR PEAKUP 24.1 CYCLE 1 Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 24.1 USE SPEC ------------------------------------------------------------------------------------------------------------------------------------ 25 HD112185 HRS ACQ 2.0 MIRROR-A2 FAINT=6560.5 1 5S 1 1 ONBOARD ACQ FOR SEARCH-SIZE=5 25.01 LOCATE=YES CYCLE 1 AFTER 15 BY 120H +/- 2 H Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 25.01 HD112185 HRS ACQ/ 2.0 MIRROR-A2 1 9.2S 1 1 ONBOARD ACQ FOR PEAKUP 25.1 CYCLE 1 Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 25.1 USE SPEC ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 2800c [ 10] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ^ ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ACCUM ^ ACQ ACQ/PEAKUP ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FP-SPLIT=STD FAINT=6560.5 SEARCH-SIZE=5 LOCATE=YES ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO/AM ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 1.80 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category STELLAR ASTROPHYSICS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 1 / 1.5-11 GROUP 2-11 NON-INT ONBOARD ACQ FOR 15.01; CYCLE 1; ONBOARD ACQ FOR 15.1; CYCLE 1 ONBOARD ACQ FOR 16.01; AFTER 15 BY 12H +/- 2 H; ONBOARD ACQ FOR 16.1; ONBOARD ACQ FOR 17.01; AFTER 15 BY 24H ONBOARD ACQ FOR 17.1; ONBOARD ACQ FOR 18.01; AFTER 15 BY 36H ONBOARD ACQ FOR 18.1; ONBOARD ACQ FOR 19.01; AFTER 15 BY 48H ONBOARD ACQ FOR 19.1; ONBOARD ACQ FOR 20.01; AFTER 15 BY 60H +/- 2 H; ONBOARD ACQ FOR 20.1; ONBOARD ACQ FOR 21.01; AFTER 15 BY 72H ONBOARD ACQ FOR 21.1; ONBOARD ACQ FOR 22.01; AFTER 15 BY 84H ONBOARD ACQ FOR 22.1; ONBOARD ACQ FOR 23.01; AFTER 15 BY 96H ONBOARD ACQ FOR 23.1; ONBOARD ACQ FOR 24.01; AFTER 15 BY 108H ONBOARD ACQ FOR 24.1; ONBOARD ACQ FOR 25.01; AFTER 15 BY 120H ONBOARD ACQ FOR 25.1; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-A2 ECH-B ^ ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD112185 ------------------------------------------------------------------------------------------------------------------------------------